1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display (LCD) device and a method of fabricating the same.
2. Discussion of the Related Art
Until recently, display devices have typically used cathode-ray tubes (CRTs). Presently, much effort and research is underway to develop various types of flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays, and electro-luminescence displays (ELDs), as a substitute for CRTs. Of these flat panel displays, LCD devices have many advantages, such as high resolution, light weight, thin profile, compact size, and low voltage power supply requirements.
In general, an LCD device includes two substrates that are spaced apart and face each other with a liquid crystal material interposed between the two substrates. The two substrates include electrodes that face each other such that a voltage applied between the electrodes induces an electric field vertically across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device. Thus, the LCD device displays images by varying the intensity of the induced electric field.
The LCD device wherein the electric field is induced vertically has a disadvantage of a narrow viewing angle. To improve the viewing angle, an in-plane switching mode LCD (IPS-LCD) device is suggested.
FIG. 1 is a perspective view illustrating an IPS-LCD device according to the related art.
Referring to FIG. 1, the IPS-LCD device 10 includes an array substrate B2, a color filter substrate B1 and a liquid crystal layer (not shown) between the two substrates B1 and B2.
The array substrate B2 includes gate and data lines 22 and 34, respectively, crossing each other to define a pixel region P on a first substrate 20. A thin film transistor T is located at a crossing of the gate and data lines 22 and 34. The thin film transistor T includes a gate electrode 26, a semiconductor layer 28 and source and drain electrodes 30 and 32.
A pixel electrode 36 and a common electrode 38 alternate in the pixel region P. The pixel electrode 36 is connected to the drain electrode 32, and the common electrode 38 is connected to a common line 24. The common line 24 is parallel with the gate line 22.
The color filter substrate B1 includes red (R), green (G) and blue (B) color filter patterns 44a, 44b and 44c in respective pixel regions P and a black matrix 42 between the color filter patterns 44a, 44b and 44c, on a second substrate 40. A planarization layer 45 is located on the color filter patterns 44a, 44b and 44c. 
Because the pixel and common electrodes 36 and 38 alternate in the same substrate, an in-plane electric field parallel with the substrate is induced. Liquid crystal molecules operate according to the in-plane electric field to display images with a wide viewing angle.
However, because the in-plane electric fields in regions between the pixel and common electrodes 36 and 38 have the same direction and the liquid crystal molecules in the regions are arranged in the same direction, a color shift may result at some angles.
To resolve the problem, an IPS-LCD device having dual domains is suggested. One of the dual domains is symmetrical to the other, and in-plane electric fields in dual domains are symmetrical to each other. Accordingly, dual domains compensate for each other, and color shift can be prevented.
FIG. 2 is a view illustrating an IPS-LCD device having dual domains according to the related art. The IPS-LCD device of FIG. 2 is referred to as a super IPS-LCD (S-IPS-LCD) device.
Referring to FIG. 2, a pixel region P has first and second regions D1 and D2. A pixel electrode 52 and a common electrode 50 alternate in each of the first and second regions D1 and D2. An arrangement of the pixel electrode 52 and the common electrode 50 in the first region D1 is symmetrical with an arrangement of the pixel electrode 52 and the common electrode 50 in the second region D2. A plurality of first domains defined by the pixel electrode 52 and the common electrode 50 in the first region D1 are symmetrical with a plurality of second domains defined by the pixel electrode 52 and the common electrode 50 in the second region D2.
Accordingly, an in-plane electric field in the first domain is symmetrical with an in-plane electric field in the second domain, and an arrangement of liquid crystal molecules 54a in the first domain is symmetrical with an arrangement of liquid crystal molecules in the second domain 54b. This symmetry makes the first and second domains compensate for each other, and thus color shift can be minimized.
However, in a middle region G, liquid crystal molecules are arranged abnormally. Accordingly, disclination occurs, and thus display quality is reduced.